TY - JOUR

T1 - Electrophoresis of tightly fitting spheres along a circular cylinder of finite length

AU - Sherwood, J. D.

AU - Ghosal, S.

N1 - Publisher Copyright:
© The Author(s), 2021. Published by Cambridge

PY - 2021/12/25

Y1 - 2021/12/25

N2 - Electrophoresis of a tightly fitting sphere of radius along the centreline of a liquid-filled circular cylinder of radius is studied for a gap width. We assume a Debye length, so that surface conductivity is negligible for zeta potentials typically seen in experiments, and the Smoluchowski slip velocity is imposed as a boundary condition at the solid surfaces. The pressure difference between the front and rear of the sphere is determined. If the cylinder has finite length, this pressure difference causes an additional volumetric flow of liquid along the cylinder, increasing the electrophoretic velocity of the sphere, and an analytic prediction for this increase is found when. If identical, well-spaced spheres are present, the electrophoretic velocity of the spheres increases with, in agreement with the experiments of Misiunas & Keyser (Phys. Rev. Lett., vol. 122, 2019, 214501).

AB - Electrophoresis of a tightly fitting sphere of radius along the centreline of a liquid-filled circular cylinder of radius is studied for a gap width. We assume a Debye length, so that surface conductivity is negligible for zeta potentials typically seen in experiments, and the Smoluchowski slip velocity is imposed as a boundary condition at the solid surfaces. The pressure difference between the front and rear of the sphere is determined. If the cylinder has finite length, this pressure difference causes an additional volumetric flow of liquid along the cylinder, increasing the electrophoretic velocity of the sphere, and an analytic prediction for this increase is found when. If identical, well-spaced spheres are present, the electrophoretic velocity of the spheres increases with, in agreement with the experiments of Misiunas & Keyser (Phys. Rev. Lett., vol. 122, 2019, 214501).

KW - colloids

KW - electrokinetic flows

KW - microfluidics

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U2 - 10.1017/jfm.2021.892

DO - 10.1017/jfm.2021.892

M3 - Article

AN - SCOPUS:85119211731

VL - 929

JO - Journal of Fluid Mechanics

JF - Journal of Fluid Mechanics

SN - 0022-1120

M1 - 2021892

ER -